The present invention relates to a resist and a process for forming a resist pattern. More particularly, the invention relates to a poly(thiocarbonyl fluoride) resist which is sensitive to an ionizing radiation and a process for forming a resist pattern by forming the resist film on a substrate, irradiating the film with an ionizing radiation and developing with an organic solvent.
Various resist materials have been employed in the preparation of semiconductor integrated circuits, and for development of the integrated circuits, a study for making a circuit pattern finer becomes a great subject of the day. Particularly, in integrated circuits having high integration such as very large scale integrated circuits, it is necessary to form a fine pattern less than 1 .mu.m in width, and vigorous efforts to develop resist materials have been made for the purpose.
Polymethyl methacrylate is put to practical use as a positive type resist. The sensitivity of this resist is about 1.times.10.sup.-4 coulomb/cm.sup.2 and the .gamma. value showing resolution is about 3.3. A poly(fluoroalkyl methacrylate) is also known as a resist material having excellent sensitivity and .gamma. value from Japanese Patent Publication No. 24088/1980, and some poly(fluoroalkyl methacrylate) has a sensitivity of 4.times.10.sup.-7 coulomb/cm.sup.2. Also, the .gamma. value of the poly(fluoroalkyl methacrylate) is within a range of from about 4.5 to about 10. The polymers of this kind have the defect, and it is reported in Japanese Patent Publication No. 30613/1980 that the polymers are poor in adhesion property to substrates such as silicon dioxide, silicon and silicon nitride and a developer often soaks into the interface between the resist film and the substrate during the development to cause the resist film to peel off.
It is an object of the present invention to provide a resist having excellent resolution, sensitivity and adhesion properties.
A further object of the invention is to provide a resist capable of forming a fine resist pattern.
Another object of the invention is to provide a process for forming a fine resist pattern.
These and other objects of the present invention will become apparent from the description hereinafter.